Ingrown toenail, in medical terms called paronychia, is a condition of swelling and inflammation of the skin around the toenails and hands caused by bacteria or fungi. This inflammation can occur suddenly (acute paronychia) or gradually (chronic paronychia).[2][3] Sometimes, this inflammation can lead to pus in the swollen area.[4] Treatment is done by using drugs that contain antibiotics to kill germs or which contain antifungals for infections caused by fungi. Source wikipedia